Questions regarding the 430N
Is it possible to use the Navigation without hearing the radio? I found that the radio volume can be dialed down to mute retaining the nav volume which brings me to my second question. How is the nav volume adjusted without having to wait for a prompt and then fiddling with the volume knob?

Questions regarding the 430N
Is it possible to use the Navigation without hearing the radio? I found that the radio volume can be dialed down to mute retaining the nav volume which brings me to my second question. How is the nav volume adjusted without having to wait for a prompt and then fiddling with the volume knob?

I think if you adjust the Nav volume during any Nav announcement, that volume will stick and become the Nav volume from that point on. I don't think you can preset the Nav volume in any options or preferences screen. I think you'll find that all volume settings (radio, phone, nav) are "sticky" and will be remembered and used in future uses of each function.